How reliable is that?

[Svartalf]

So I'm watching a documentary (or sensationalist codswollop) about the so called desert glass found in Western Egypt/Eastern Lybia. They say it's from a meteorite impact and assert that proof of it is that the glass contains traces (or abnormally abundant traces) of the platinide metals iridium and osmium.

So I know about meteoric iron (or nickel iron), but never heard of platinum group metal meteorites... so, how much shit are the doc makers trying to make me swallow, or am I an ingrate ass not to recognize truthiness when it's shoved at me for once?

[JimC]

I know that one of the signs of a large impact at the KT boundary was a sudden increase in Iridium and Osmium levels in sediments at that time, so it makes sense to me...

[Svartalf]

okay, I did not know that, I'm just surprised that such metals should be so common in meteors... they 'dated' (for what it's worth) the impact at only 30 million years ago, so it would be a different meteorite than the chicxulub one that supposedly ushered in the Tertiary era.

[JimC]

okay, I did not know that, I'm just surprised that such metals should be so common in meteors... they 'dated' (for what it's worth) the impact at only 30 million years ago, so it would be a different meteorite than the chicxulub one that supposedly ushered in the Tertiary era.

That one ejected so much dust, which eventually settled worldwide, leaving a signature in sedimentary rocks all over the world. And it's not that these space rocks are made of these metals, just that they have elevated levels compared to the Earth's crust. Most of the world's original helping of Osmium et al settled deep into the molten core long ago, which is why they are so rare and precious today...

[Svartalf]

well, the day I marry, I'd rather have an iridide platinum ring than a gold one, of course, I'll likely die a bachelor and leave all my estate to my brother or nephew